Here’s a great then and now comparison of the Pepco substation located at Harvard Street and Sherman Avenue. Substation No. 13 was built in 1907 and designed by architect Frederick B. Pyle. Currently, it is Pepco’s oldest operating substation and one of the oldest purpose-built substation buildings still standing. To keep up with demand, additions were also constructed in 1920, 1921, 1929, and 1944.